Diagnostic testing sensors for resonant detectors

ABSTRACT

Biosensor apparatus and associated method for detecting a target material using a vibrating resonator having a surface that operably interacts with the target material. A detector is in electrical communication with a sensor, the sensor comprising a first paddle assembly connected to a second paddle assembly, the first paddle assembly having at least one microbalance sensing resonator proximate a proximal end and at least one sensing electrical contact proximate a distal end in electrical communication with the sensing resonator. The at least one sensing resonator has a target coating for operably interacting with the target material, and the second paddle assembly has a microbalance reference resonator proximate the proximal end and at least one reference electrical contact proximate the distal end in electrical communication with the reference resonator.

PRIOR APPLICATION

This Application claims the benefit of U.S. Provisional Application No.61/355,409 filed Jun. 16, 2010, the disclosure of which is incorporatedby reference herein.

FIELD OF THE INVENTION

The present invention relates to sensors, and more specifically to asensor for diagnostic measuring or testing based on vibrating resonatorsthat measure and compare a shift in resonance characteristics as itinteracts with certain detected materials.

BACKGROUND OF THE INVENTION

There are a variety of sensors within the art for diagnostic testing ofmaterials related to human health, veterinary medical, environmental,biohazard, bioterrorism, agricultural commodity and food safety. Themeans for diagnostic testing and analysis of chemical and/or biologicalmaterials at the point of need remains limited. Diagnostic testingtraditionally requires long response times to obtain meaningful data,involves expensive remote or cumbersome laboratory equipment that coststhousands of dollars located in a centralized laboratory, requires largesample sizes, utilizes multiple reagents, demands highly trained users,may require numerous steps, and/or involves significant direct andindirect costs. For instance, in both the veterinary and humandiagnostic markets, most tests require that a specimen be collected fromthe patient and sent to the laboratory, but the results are notavailable for several hours or days later. As a result, the patient mayleave the caregiver's office without confirmation of the diagnosis andthe opportunity to begin immediate treatment.

Other problems related to portable devices include diagnostic resultsthat are limited in sensitivity and reproducibility compared toin-laboratory testing. Fast response times are desirable and oftencritical to the identification of chemical and/or biological materials,such as in providing timely medical attention or in averting the spreador exposure of public health threats. Direct costs relate to the labor,procedures, and equipment required for each type of analysis. Indirectcosts partially accrue from the delay time before actionable informationcan be obtained, e.g., in medical analyses or in the monitoring ofchemical processes. Many experts believe that the simultaneous diagnosisand treatment enabled by an effective point of need diagnostic testingsystem would yield clinical, economic and social benefits. For instance,clinical benefits include faster turnaround of results, reduced time totreatment, reduced disease severity and improved mortality/morbidity.Economic benefits included reduced length of stay, improved utilization,more efficient care delivery and fewer admissions. Social benefitsinclude improved access to healthcare/therapy, higher patientsatisfaction and reduced absenteeism.

Various technologies have been utilized to develop sensors to detect andanalyze chemical and/or biological materials, but fail to address issuesrelated to traditional detection and analysis systems. For example, somedetection systems determine the presence of substances based onelectrochemical reactions. Such electrochemical sensors, however,usually have complex sensor arrangements that requiresubstance-recognizing agents, are expensive, are often difficult tominiaturize due to low current densities resulting from smaller sensorstructural shapes, and the rate and efficiency of the electrochemicalsensor response time may be undesirable as they are controlled by thechemical reactions. Other detection systems are known from chemicallaboratory practice, such as the various types of chromatography andspectral analysis. The laboratory systems, however, often do not meetthe demands for ruggedness, stability, transportability, and lowmaintenance and energy consumption required for diagnostic testingoutside the laboratory. Bench-top instruments are also often veryexpensive and require a centralized laboratory to which samples must besent for testing.

Resonators based on piezoelectric properties of materials have also beenused in detecting very small quantities of materials. Piezoelectricresonators used as sensors in such applications are sometimes called“micro-balances.” A piezoelectric resonator is typically constructed asa thin planar layer of crystalline piezoelectric material sandwichedbetween two electrode layers. When used as a sensor, the resonator isexposed to the material being detected to allow the material to bind ona surface of the resonator.

A conventional way of detecting the amount of the material bound on thesurface of a sensing resonator is to operate the resonator as anoscillator at its resonant frequency, as described, for instance, inU.S. Pat. No. 5,932,953 entitled “Method and System for DetectingMaterial Using Piezoelectric Resonators,” which is incorporated byreference herein. As the material being detected binds on the resonatorsurface, the oscillation frequency of the resonator is reduced. Thechange in the oscillation frequency of the resonator, caused by thebinding of the material on the resonator surface, is measured and usedto calculate the amount of the material bound on the resonator or therate at which the material accumulates on the resonator surface.

The sensitivity of a piezoelectric resonator as a material sensor istypically proportional to its resonance frequency. Thus, thesensitivities of material sensors based on the popular quartz crystalresonators are limited by their relatively low oscillating frequencies,which typically range from several MHz to about 100 MHz. The developmentof thin-film resonator (TFR) technology has produced sensors withsignificantly improved sensitivities. A thin-film resonator is formed bydepositing a thin film of piezoelectric material, such as AlN or ZnO, ona substrate. Due to the small thickness of the piezoelectric layer in athin-film resonator, which is on the order of several microns (μm), theresonant frequency of the thin-film resonator is on the order of 1 GHzor higher. The high resonant frequencies and the corresponding highsensitivities make thin-film resonators useful for material sensingapplications.

A significant disadvantage of the conventional approach is thedifficulty in separating the real intended material binding signal fromspurious environmental effects. During material detection, a sensingresonator is often exposed to different environmental conditions thatalso tend to alter the resonance properties of the resonator. It isoften difficult to isolate the resonance changes caused by the materialdetected from the resonance changes caused by various environmentalconditions without incorporating large, expensive means forenvironmental isolation.

What is still needed is a simple sensor and resonance shift detectionsystem that is portable for point of need diagnostic testing of chemicaland/or biological materials, which not only is simple to use with littleor no training, but provides rapid turn-around of reproduciblyconsistent results at acceptable sensitivity levels, capable ofembodiments that can be scaled for manufacturing level utilization, lowcost, and capable of transmitting results anywhere to caregivers andpatient information systems.

BRIEF SUMMARY OF THE INVENTION

Embodiments of the present invention meet the need for a simple,effective, cost-efficient, reliable, repeatable, sensor for resonanceshift detection of chemical and/or biological materials. These samplematerials are generally in the form of a fluid including, for instance,liquids, gasses, granular suspensions, gels, and the like. Resonanceshift detection, in various embodiments, can be based on phase shift orfrequency shift. In some embodiments of the invention, the resonanceshift detection system includes a portable hand-held resonance-shiftdetector and a sensor connected by an interconnector, that can be usedfor point of need diagnostic testing in the field. In other embodimentsof the invention, the resonance shift detection system includes alaboratory bench resonance shift detector and a sensor connected by aninterconnector. In still other embodiments, the resonance shift detectorand sensor are directly connected without an interconnector.

One aspect of the invention is directed to a sensor for a biosensorinstrument comprising a first paddle assembly and a second paddleassembly. The first paddle assembly includes a first substrate having aproximal end, a distal end, a front surface and a back surface, amicrobalance sensing resonator assembly attached to the front surface ofthe first substrate proximate the proximal end, and at least one sensingelectrical contact proximate the distal end in electrical communicationwith the sensing resonator assembly. The second paddle assembly isconnected to the first paddle assembly, and includes a second substratehaving a proximal end, a distal end, a front surface and a back surface,a microbalance reference resonator assembly attached to the frontsurface of the second substrate proximate the proximal end, and at leastone reference electrical contact proximate the distal end in electricalcommunication with the reference resonator assembly. The first andsecond paddle assemblies are connected such that the sensing andreference resonator assemblies are on a proximal end of the sensor. Thesensing resonator assembly comprises at least one sensing resonatorcoated with a testing material that operably interacts with a targetmaterial, such as by binding with the target material.

According to another aspect, an apparatus for detecting a targetmaterial includes a sensor having a proximate end and a distal end, thesensor comprising a first paddle assembly connected to a second paddleassembly, the first paddle assembly having at least one sensingresonator proximate the proximal end and at least one sensing electricalcontact proximate the distal end in electrical communication with thesensing resonator, the second paddle assembly having a referenceresonator proximate the proximal end and at least one referenceelectrical contact proximate the distal end in electrical communicationwith the reference resonator, wherein the at least one sensing resonatorhas a target coating for operably interacting with the target material,such as by binding to the target material. The apparatus furtherincludes a detector in electrical communication with the sensor.

A method of detecting a target material according to another aspect ofthe invention includes providing an apparatus for detecting the targetmaterial, the apparatus comprising a detector in electricalcommunication with a sensor, the sensor comprising a first paddleassembly connected to a second paddle assembly, the first paddleassembly having at least one sensing resonator proximate a proximal endand at least one sensing electrical contact proximate a distal end inelectrical communication with the sensing resonator, the at least onesensing resonator having a target coating for operably interacting withthe target material, and the second paddle assembly having a referenceresonator proximate the proximal end and at least one referenceelectrical contact proximate the distal end in electrical communicationwith the reference resonator. The method further includes contacting thesensing resonator and the reference resonator with a test sample.

The above summary of the various representative embodiments of thepresent invention is not intended to describe each illustratedembodiment or every implementation of the invention. Rather, theembodiments are chosen and described so that others skilled in the artmay appreciate and understand the principles and practices of theinvention. The figures in the detailed description that follows moreparticularly exemplify these embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention may be more completely understood in consideration of thefollowing detailed description of various embodiments of the inventionin connection with the accompanying drawings, in which:

FIG. 1A is a functional block diagram of a hand-held resonance shiftdetector system according to one embodiment of the present invention.

FIG. 1B is a functional block diagram of the hand-held resonance shiftdetector system of FIG. 1A with the sensor detached from theinterconnector according to one embodiment.

FIG. 1C is a functional block diagram of the hand-held resonance shiftdetector system of FIG. 1A with the sensor detached from theinterconnector and the interconnector detached from the instrument.

FIG. 1D is a functional block diagram of another hand-held resonanceshift detector system of the present invention in which the resonanceshift detector system and sensor are directly connected to each otherwith a connector mounted on the instrument board and without aninterconnector according to one embodiment.

FIG. 2 is a diagram of a laboratory bench resonance shift detectorsystem according to one embodiment of the present invention.

FIG. 3A is a schematic view of the resonance shift detector systemaccording to one embodiment of the present invention with theinterconnector located outside the instrument.

FIG. 3B is a schematic view diagram illustrating the resonance shiftdetector system of one embodiment with the interconnector located insidethe instrument.

FIG. 4A is an illustration of a sensor having a back-to-back paddleconfiguration according to one embodiment.

FIG. 4B is another illustration of the other side of the sensor of FIG.4A.

FIG. 5 is a side perspective view illustration of the sensor in FIGS.4A-4B further illustrating the back-to-back paddle configurationembodiment.

FIG. 6A is a schematic top view of the front side of a printed circuitboard from which the back-to-back paddle configuration embodiment isconstructed according to one embodiment.

FIG. 6B is a schematic top view of the back side of the printed circuitboard in FIG. 6A.

FIG. 6C is a schematic view of the various layers of the printed circuitboard in FIGS. 6A-6B.

FIG. 7A is a schematic top view of a resonator assembly according to oneembodiment of the present invention.

FIG. 7B is a schematic of a cross sectional view of the resonatorassembly of FIG. 7A.

FIG. 8A is a perspective schematic of a sensor assembly within a sensorhousing assembly according to one embodiment of the present invention.

FIG. 8B is an exploded perspective schematic of the sensor assemblywithin the sensor housing assembly of FIG. 8A.

FIG. 8C is a perspective schematic of the sensor assembly within thesensor housing assembly of FIG. 8A with a top portion of the sensorhousing assembly removed.

FIG. 8D is another perspective schematic of the sensor assembly withinthe sensor housing assembly of FIG. 8A with the top portion of thesensor housing assembly removed.

FIG. 9A is a side perspective schematic of a sensor assembly within asensor housing assembly according to one embodiment of the presentinvention.

FIG. 9B is a top perspective schematic of the sensor assembly within thesensor housing assembly of FIG. 9A.

FIG. 10A is a side perspective schematic of a sensor assembly within asensor housing assembly according to one embodiment of the presentinvention.

FIG. 10B is a top perspective schematic of the sensor assembly withinthe sensor housing assembly of FIG. 10A.

FIGS. 11A-11M illustrate a process for the manufacture of the sensoraccording to one embodiment of the present invention.

FIG. 12A is a schematic of another embodiment of a sensor configurationof the present invention.

FIG. 12B is a schematic of the sensor configuration of FIG. 12A within asensor housing assembly of the present invention.

While the invention is amenable to various modifications and alternativeforms, specifics thereof have been shown by way of example in thedrawings and will be described in detail. It should be understood,however, that the intention is not to limit the invention to theparticular embodiments described. On the contrary, the intention is tocover all modifications, equivalents, and alternatives.

DETAILED DESCRIPTION

While this invention may be embodied in many different forms, there aredescribed in detail herein specific preferred embodiments of theinvention. This description is an exemplification of the principles ofthe invention and is not intended to limit the invention to theparticular embodiments illustrated.

In some embodiments, sensors for resonance shift detection of chemicaland/or biological materials include two printed circuit boards (“PCB”),each with a single resonator die thereon, configured back-to-back suchthat the sensor has one sensing resonator and one reference resonatordisposed on separate substrates. In the back-to-back PCB configuration,the backsides of two substantially identical configured PCBs are securedtogether such that the electrical contact section of each PCB is on oneend of the sensor and each resonator on each PCB is on the other end ofthe sensor. The back-to-back PCB configuration provides a closeproximity of the two resonators, which likely have closely matchedresonant frequencies and phase responses. The close proximity ensuresthat the two resonators are subjected to substantially identicalenvironmental conditions during a material sensing operation. The sensoreffectively allows accurate phase shift or resonant frequency shiftmeasurements and cancellation of environmental effects during materialsensing operations. In some embodiments, the resonators on the PCB areoff-center such that the back-to-back PCB configuration contains offsetresonators with sufficient distance there between to reduce cross talkbetween the two resonators and not affect the flow of the sample liquid.

In some embodiments, the sensors for resonance shift detection includeback-to-back PCB configurations utilizing two substantially differentPCBs. In one aspect of the present invention, the resonator on one PCBis off-center while the resonator on the other PCB is centered. In thisconfiguration, the reference and sensing resonators may still havesufficient distance there between to reduce cross talk between the tworesonators. In another aspect of the present invention, the resonatorson the two PCBs are such that the back-to-back PCB configuration resultsin the reference and sensing resonators being directly opposed. Crosstalk between the resonators may be reduced or eliminated by theresonators being sufficiently separated or other means for cross talkelimination.

In some embodiments, the sensing resonator is coated with a differentmaterial than the reference resonator depending upon the material to bedetected. By merely changing the coating on the resonators, theresonance shift detection system allows universal use for variousdiagnostic testing of chemical and/or biological materials withoutchanging any of the other system structural components.

Sensors for resonance shift detection of chemical and/or biologicalmaterials effectively allow fast response times for the detection of therespective chemical and/or biological material, in the field detectioncapabilities, small sample sizes, minimally trained individuals, lowdirect and indirect costs, and electronically transmittable data.

In accordance with these and other aspects of the present invention,there is provided a sensor with a back-to-back paddle configuration,wherein each paddle includes a printed circuit board and at least onesensing resonator assembly and at least one reference resonatorassembly, and at least a portion of the sensor within a sensor housingassembly, wherein the sensor housing assembly includes a sample channelfor the introduction of the liquid sample to the at least one sensingresonator and at least one reference resonator.

In some embodiments, the resonance shift detection system includes areusable handheld battery or solar-powered electronic instrument, and aneasily mounted disposable sensor that may be contained within a sensorhousing assembly. The sensor has a biological coating that specificallybinds with the desired target molecule and provides the mechanism ofdetection and quantification. A specimen (whole blood, urine, saliva, orany other liquid) is drawn into the single-use sensor within the sensorhousing assembly. Signals returned from the sensor (i.e. a change inphase or resonant frequency of the RF wave) indicate if the target ispresent, and if present, its concentration. For each analysis, a newsensor is attached to the instrument.

In some embodiments, the resonance shift detection system utilizes radiofrequency resonators operating in shear wave mode. As these resonatorsoperate they generate radio frequency waves that propagate into theliquid layer above the resonator. Changes in the viscosity of thisliquid layer result in changes in the resonant characteristics of theresonator. The resonator surface is coated with a detection moleculesuch as a target specific antibody. As the sensor is exposed to asample, binding of the target to the antibody causes a change in theresonance characteristics of the resonator. The rate of this change canthen be used to give either a qualitative (yes/no) to identify presence,and a quantitative result (mg/dL) to determine concentration.

In some embodiments, each sensor has two resonators—a test (sensing) anda reference resonator. The reference resonator serves as an internalcontrol and accounts for resonance changes resulting from non-specificbinding, noise, or other changes in environmental conditions. Thesensors are very small, thus enabling several resonators to be mountedon a single disposable sensor for testing several infectious agents ormultiple pathogens at the same time on a single specimen such asmultiple viral infections, several bio-warfare agents, several food orenvironmental contaminants, or the precise identification of aninfluenza virus' subtype.

In some embodiments, the rate of the resonance change varies with theconcentration of the target. The rate of change of resonant frequency orphase angle for the most concentrated sample occurs faster than thelowest concentrated sample.

In some embodiments, the resonance shift detection system provides theuser with a simple diagnostic testing platform that is inexpensiveenough for worldwide deployment and provides several features andadvantages over existing diagnostic testing systems, including, atleast:

Existing Systems Present Invention Results 10 to 30 minutes 60 secondsor less Instrument Cost $2,000-$5,000 $150-$250 Size and portabilityLarge, not field Size of cell phone, portable portable Number of StepsMultiple, many manual One, automated Sensitivity Insensitive lateralflow Highly sensitive sensor Requires reagents/supplies Yes NoComplexity Complex Simple Requires skilled operator Yes No EnvironmentLab/Institutional Setting Any Environment

The resonance shift detection system is ideal for detecting pathogens,proteins and bio-molecules in whole blood, urine, saliva, water, andother liquids and may be an effective tool for screening and diagnosinginfections such as, for example, HIV, Smallpox, SARS, influenza(including swine flu or H1N1), and any other molecular biomarkers. Theresonance shift detection system may make emerging proteomic diagnostics(measuring many biomarkers simultaneously to diagnose, monitor diseaseprocesses and therapy effectiveness over time) widely available and easyto use, providing an affordable means for measuring biomarkers for theearly detection of various forms of cancer, heart disease or stroke, thediscovery of metabolic diseases, the monitoring of tissue and organhealth during recovery and rehabilitation, and for the examination oftreatment effectiveness and compliance in chronic diseases, as well as ahost of other applications.

Referring now to the figures, the components of the resonance shiftdetector system of the present invention are illustrated. In someembodiments, the resonance shift detector system can be relatively smallin size to be portable such that it can be utilized in the field forspecific diagnostic testing applications. In some other embodiments, theresonance shift detector system can be configured for diagnostic testingin a laboratory setting. As shown in FIGS. 1A-1C, the resonance shiftdetector system 10 is illustrated in a hand-held or portableconfiguration that includes an instrument 20 a capable of beinginterfaced with a sensor 30 by an interconnector 60, which can be usedfor point of need diagnostic testing in the field. As shown in FIG. 1D,the resonance shift detector system 10 is illustrated in a hand-held orportable configuration that includes an instrument 20 a with a sensorconnector 66 that is capable of directly electrically interfacing withsensor 30.

As shown in FIG. 2, the resonance shift detector system 10 isillustrated in a laboratory-bench or more permanent configuration thatincludes an instrument 20 b, such as a Network Analyzer, capable ofbeing interfaced with a sensor 30 by an interconnector 60. The sensor 30mounted on an interconnector 60 and coupled to a laboratory-benchinstrument 20 b, such as a Network Analyzer, allows diagnostic testingin a laboratory setting, quality control testing of a batch of sensorsduring production, and/or the development of coatings on the sensor 30for target material diagnostic testing.

The instrument 20, including, but not limited to hand-held instrument 20a and laboratory-bench instrument 20 b, may have means for connection tothe internet or otherwise transferring information, such as one or moreUSB ports, wireless connection, or the like.

FIGS. 3A and 3B also show the instrument 20, whether a hand-heldinstrument 20 a or a laboratory-bench instrument 20 b, capable of beinginterfaced to the sensor 30 by the interconnector 60. The sensor 30 hasa one-port sensing resonator 44 and a one-port reference resonator 54. Aone-port resonator has an electrode that is used for both signal inputand output. The other electrode of the one-port resonator is typicallygrounded. The hand-held instrument 20 generally includes a signal source21 that provides an input signal of a frequency which is within theoverlapping portion of the resonant bands of the resonators and in someaspects is set equal to the average of the resonance frequencies of thetwo resonators. The input electrical signal provided by the signalsource 21 is split by a power divider 22 and the split signals arecoupled through couplers 23, 24 to the respective sensing and referenceresonators 44, 54. In this example embodiment, the phase angle of eachresonator is the resonant characteristic that is being monitored. Theoutput signals of the resonators are directed to the phase detector 25by the respective couplers 23, 24 as sensor and reference signals. Boththe input electrical signals and the output signals of the resonatorspass through the interconnector 60 between the couplers 23, 24 and therespective sensing and reference resonators 44, 54. The phase detector25 processes the sensor and references signals to produce an outputsignal indicative of a phase difference between the sensor and referencesignals, which is caused mainly by the binding of the material beingdetected on the surface of the sensing resonator 44. In someembodiments, a separate signal source 21 can provide an input signal ofa frequency for each of the respective resonators, which would eliminatethe use of a power provider 22.

In one example embodiment, sensing and reference resonators 44, 54 areresonator assemblies that each include a piezoelectric crystal that isabout 150-300 microns wide, and are formed on a silicon substrate, whichis about 0.5×1 mm in size. The silicon substrate is mountable on aprinted circuit board using solder bumps on a surface opposite thesurface on which the sensing and reference resonators are formed (e.g.,a “flip-chip” configuration).

The phase detector 25 in the illustrated embodiment includes adouble-balanced mixer 26 (or a mathematic multiplier) which receives thesensor and reference signals. The output of the mixer 26 is passedthrough a low-pass filter 27 which eliminates a time dependent term andleaves only the DC term as the output 28 of the phase detector 25. Asprovided in more detail in U.S. Pat. No. 5,932,953, which isincorporated by reference herein, the resulting measured phase shiftchange can be used to derive the total amount of the material bound onthe surface of the sensing resonator 44. In some embodiments, the signalsource 21 generates an analog signal and the phase detector 25 generateseither an analog or a digital output signal 28 after receiving thesignal and reference signals and processing the information therefrom.In some embodiments, the signal from each respective resonator 44, 54 isdirected to a separate respective phase detector 25, each respectivephase detector 25 processing the respective sensor or reference signalto produce a phase signal indicative of a phase shift that are thencompared to each other to determine the net difference in phase shiftbetween the sensing and reference resonators, which is caused by thebinding of the material being detected on the surface of the sensingresonator 44. Although this illustrative example describes a phase shiftdetection embodiment, it should be understood that other suitablearrangements may be implemented by persons skilled in the art thatdetect changes in another resonance characteristic, such as changes inresonant frequency, while implementing aspects of the inventiondescribed herein (which are generally applicable to resonance sensors ofdifferent types).

In some embodiments, as shown in FIGS. 4A-4B and 5, sensor 30 comprisesa first paddle 40 mounted in a back-to-back paddle configuration with asecond paddle 50. The first paddle 40 and the second paddle 50 haveessentially the same configuration such that the back-to-back paddleconfiguration results in a sensor 30 with a symmetrically opposedconfiguration. In some embodiments, each paddle comprises a substratesuch as a printed circuit board with at least one resonator assemblymounted thereon. As illustrated in the figures, the first paddle 40contains a first printed circuit board 42 with a sensing resonatorassembly 44 mounted thereon on one end and a contact set 46 located onthe opposite end. The second paddle 50 contains a second printed circuitboard 52 with a reference resonator assembly 54 mounted thereon on oneend and a contact set 56 located on the opposite end. Both the sensingresonator assembly 44 and the reference resonator assembly 54 may becantilevered over the end of the respective printed circuit board 42,52. In some aspects, the sensing resonator assembly 44 is coated with atest reagent that binds to or captures the specific material to bedetected during the diagnostic testing. In some aspects, the referenceresonator assembly 54 is coated with a reference reagent that does notbind with or otherwise capture the specific material to be detectedduring the diagnostic testing. The resonator assembly 44, 54cantilevered over the end of the respective printed circuit board 42, 52provides full access of the resonator 44 a, 54 a to facilitate reagentcoating applications as well as exposure to the testing sample duringdiagnostic testing.

The sensor 30 may be of various shapes and sizes. In some embodiments,the sensor 30 with back-to-back paddles 40, 50 has the shape illustratedin FIGS. 4A-6C, which allows the resonator side of the sensor 30 to beinserted into a well of a standard 96 well plate. For instance, paddles40, 50 can be approximately 2-3 cm along their longitudinal dimension,and 0.5-1.5 cm along their transverse dimension. In some embodiments,the two ends of the sensor 30 (contact set end and resonator end) aredifferent widths such that there is a shoulder region that prohibits thesensor 30 from being inserted too far into a well of the standard 96well plate. In some embodiments, the two ends of the sensor 30 are thesame width, as illustrated for example in FIG. 11L.

In some aspects, as illustrated in FIGS. 4A-4B, the resonator assembly44, 54 is attached to the printed circuit board 42, 52, respectively, inan off-center configuration. The off-center configuration allows anoffset between the resonator assemblies 44 and 54 in the back-to-backpaddle configuration, which may reduce cross talk during operation andnot prevent the flow of the liquid sample during diagnostic testing. Insome aspects, the resonator assemblies 44 and 54 are configured suchthat they are directly offset in the back-to-back paddle configuration,whether the resonator assemblies 44 and 54 are centered on therespective printed circuit board or otherwise off-set such that they atleast partially overlap in the back-to-back paddle configuration.

While the foregoing description has identified the paddles 40, 50 ofcontaining either one of a sensing resonator assembly or referenceresonator assembly on a printed circuit board, the back-to-back paddleconfiguration allows the sensor 30 to contain one or more resonators oneach of the respective printed circuit boards 42, 52. For instance, inone type of embodiment, paddle 40 contains two or more sensingresonators and paddle 50 contains two or more reference resonators. Inother embodiments, paddles 40, 50 each contain at least one sensingresonator and at least one reference resonator. In related embodiments,paddles 40,50 may each contain various configurations of one or moreresonators (sensing and/or reference), or paddle 40 or paddle 50contains one resonator while the other contains more than one resonator.As indicated by the foregoing, various arrangements of sensingresonators and reference resonators on the respective printed circuitboard 42, 52 to constitute the paddles 40, 50 is contemplated by thepresent invention.

In some embodiments, as shown in FIGS. 4A-4B, the contact sets 46, 56contain six contacts 46 a-46 f and 56 a-56 f, respectively. Contacts 46a and 56 a connect to the ground plane 47, 57, respectively, as shown inFIG. 6C. Contacts 46 b and 56 b are connected to the signal conductor49, 59, respectively (shown in FIG. 6C) by a via 49′ to the internalportion of the respective printed circuit board 42, 52 and are connectedto the signal contacts 43 d, 53 d by a via 49″. Contacts 46 c, 46 d and56 c, 56 d connect to the ground plane 47, 57, respectively, as shown inFIG. 6C. Contact pairs 46 e and 46 f in FIG. 4A, or contact pairs 56 eand 56 f in FIG. 4B, are connected to each other.

In some embodiments with more than one resonator on the respectivepaddle 40, 50, one of ordinary skill in the art will appreciate thenumber of contacts on in contact sets 46, 56 will depend upon the numberof resonators and that each resonator will be connected to a signalcontact in the respective contact set 46, 56. In such embodiments, theremay be one or more ground contacts connected to the ground plane 47, 57and a signal contact connected to the respective resonator. In someembodiments, the contact configuration of ground, signal, groundprovides an advantage of reducing signal loss, although only one groundper one signal provides electrical continuity.

FIGS. 6A-6C further illustrate a printed circuit board 42, 52 and thelayers thereof, of the sensor 30. Since the sensor 30 in someembodiments is comprised of the back-to-back paddle configuration ofpaddles 40 and 50 that have essentially the same configuration, thefollowing description with respect to printed circuit board 42 of paddle40 shall be understood to equally apply to the printed circuit board 52of paddle 50. In some embodiments, both the sensing resonator assembly44 and the reference resonator assembly 54 attach to the respectiveprinted circuit board 42, 52 by a set of reflow solder bonds. As shownin FIG. 6A, the printed circuit board 42 contains a set of solder pads43, with solder pads 43 a-43 c being connected to the ground plane 47and solder pad 44 d being signal connected to signal contact 46 b bysignal conductor 49. Now referring to FIG. 6C, the first panelillustrates the vias 49′, 49″ that connect the signal contacts 46 b, 43d, respectively, to the signal conductor 49 in the internal portion ofthe printed circuit board 42. The second panel illustrates the topconductor layer with ground plane 47. The third panel illustrates themid-conductor layer with signal conductor 49 surrounded by a groundconductor. The fourth panel illustrates the bottom conductor layer witha ground plane. The fifth panel illustrates the ground stitching toconnect all of the ground planes in the second, third and fourth panelstogether. The sixth panel illustrates the top solder mask with a devoidspace for the contact set. The seventh panel illustrates the bottomsolder mask, and the eighth panel illustrates the routing pattern togive the printed circuit board 42 its shape. As illustrated by the threeconductor layers, the signal conductor 49 is a strip line sandwiched onall sides by ground conductor, which essentially is the equivalent of acoaxial conductor. In some embodiments, this conductor layerconfiguration creates a 50 ohm impedance matched structure.

The solder pads 43, 53 on the respective printed circuit board 42, 52are attached to a resonator assembly, whether a sensing resonatorassembly or a reference resonator assembly. Referring now to FIG. 7A,the top surfaces of a resonator assembly is illustrated, which isequally applicable to both sensing resonator assemblies and referenceresonator assemblies. For ease of reference, the following descriptionrefers to the sensing resonator assembly 44, although the description isequally applicable to the reference resonator assembly 54. Asillustrated in FIG. 7A, the top surface of the sensing resonatorassembly 44 contains a set of solder bumps 45. Solder bumps 45 a-45 care connected to ground within the resonator assembly 44. Solder bump 45d is connected to the resonator 44 a by way of a via 44 e through thepiezoelectric layer 44 d and a resonator conductor 44 c between, whichis further illustrated by the cross sectional view in FIG. 7B. When theresonator assembly 44 is attached to the printed circuit board 42 toform paddle 40, solder pad 43 a and solder bump 45 a are connected,solder pad 43 b and solder bump 45 b are connected, solder pad 43 c andsolder bump 45 c are connected, and solder pad 43 d and solder bump 45 dare connected. The resonator assembly 44 is also cantilevered over theedge of the printed circuit board 42 to allow the resonator 44 a to beexposed to the surrounding environment during the testing process. Insome embodiments, the solder pads 45 may be on a different side of theresonator assembly 44 than the resonator 44 a, such that the resonatorassembly 44 does not have a cantilevered configuration.

In building impedance matched resonators, the relative surface area ofthe resonator 44 a is directly related to the frequency at which theresonator resonates, with higher frequency resonators having a smallersurface area and lower frequency resonators having a larger surfacearea. Accordingly, it is contemplated that resonators with variousresonant frequencies may be used depending upon the desired resonantfrequency and any regulatory restrictions on the frequencies availableto be used. The thickness of the piezoelectric layer also affectsfrequency with a thinner piezoelectric resonating at a higher frequencythan a thicker layer. In various embodiments, resonance frequenciesrange from 500 MHz to 2.5 GHz or higher. For example, in certainembodiments operation at resonant frequencies up to 5 GHz, or 10 GHz, iscontemplated.

Since the back-to-back paddle configuration allows the sensing resonator44 and the reference resonator 54 to be located in a close proximitywith each other, the two resonators are subjected to substantiallyidentical environmental conditions during a material sensing operation,which allows for accurate resonance shift measurements and effectivecancellation of the environmental effects. Environmental effects thatmay be cancelled may be a result of viscosity, pH, temperature,particulates, and any other environment conditions within the samplethat will affect the sensing resonator 42 during diagnostic testing.

In some embodiments, the sensor 30 contains a sensor housing assembly 32as illustrated in FIGS. 8A-10B. The sensor housing assembly 32 mayinclude a body portion 33 that substantially contains at least a portionof the back-to-back paddles 40, 50 and a cover portion 34 that operablyengages with the body portion 33. In some embodiments, the body portion33 and the cover portion 34 are relatively the same size such that theback-to-back paddles 40, 50 are about equally contained within eachportion 33, 34. In some embodiments, the contact sets 46, 56 are exposedand not surrounded by the sensor housing assembly 32, as illustrated inFIGS. 8A-8D and 10A-10B. In some other embodiments, as illustrated inFIGS. 9A-9B, the sensor housing assembly 32 extends over at least aportion of the contact sets 46, 56 while still allowing connectionthereto.

In some aspects, the cover portion 34 is bonded to the body portion 33,such as by ultrasonic welding. The sensor housing assembly 32 may alsocontain a sample channel 35 that provides the ability for the samplealiquot to be brought into direct contact with the sensing and referenceresonator assemblies 44, 54 of the sensor 30. In some embodiments, thesample aliquot is introduced to the sensing and reference resonatorassemblies 44, 54 by capillary action. In some embodiments, the volumeof the sample aliquot introduced within the sensor housing assembly 32is between about 15 microliters to about 50 microliters. In someaspects, the sample volume within the sensor housing assembly 32 will beknown and have a relatively reproducible volume between diagnostic testssuch that quantitative assessment of the targeted material being sensedmay be ascertained. As illustrated in FIGS. 9A-10B, the sensor housingassembly 32 may also contain a venting mechanism to effectuate theintroduction of the sample aliquot to the sensing and referenceresonator assemblies 44, 54.

In some embodiments, as illustrated in FIG. 8B, paddles 40, 50 aremounted together in the back-to-back configuration with a bonding agent47, such as a tape, adhesive, glue, or the like. In one aspect, thebonding agent 47 also provides a liquid barrier that prevents the liquidsample from penetrating between the paddles 40, 50 and migrating towardsthe contact sets of the sensor 30. The body portion 33 and/or the coverportion 34 may also contain energetic director means for creating agasket seal when ultrasonically welded that also prevents the migrationof the sample aliquot on the top or side surfaces of the paddles 40, 50.For example, as illustrated in FIG. 8D, the cover portion 34 containsenergy directors 37 with corresponding energy directors on the bodyportion (not shown) for ultrasonic welding the body portion 33 and coverportion 34. In some embodiments, the sensor 30 and sensor housingassembly 32 will be used for a single diagnostic test and aredisposable. In some aspects, the back-to-back paddle configurationallows the sensor 30 to be small in size with a width being aboutthree-tenths of an inch or smaller and the length being about one inchor smaller.

Now referring back to FIGS. 1A-1C and 2, the interconnector 60 iscapable of simultaneously interfacing with the instrument 20 and thesensor 30 to enable the electrical coupling of the instrument 20 and thesensor 30. As illustrated best in FIG. 1C, the interconnector 60includes a printed circuit board 62 on which is mounted an instrumentconnector 64 and a sensor connector 66. The instrument connector 64electrically interfaces to the instrument 20 and the sensor connector 66electrically interfaces to the sensor 30. In some embodiments, theinterconnector 60 is located outside the housing of the instrument 20,as illustrated in FIG. 3A. In some embodiments, the interconnector 60 islocated inside the housing of the instrument 20, as illustrated in FIG.3B. The instrument connector 64 and sensor connector 66 may consist ofany of the connectors known to one of ordinary skill in the art,including printed circuit board edge connectors or SubMiniature versionA (“SMA”) connectors, as shown in FIGS. 1A-1C and 2. In someembodiments, both the instrument connector 64 and the sensor connector66 are printed circuit board edge connectors that electrically interfacewith printed circuit board edge connectors on the instrument and sensor,respectively. As discussed above, the sensor 30 may contain sets ofcontacts 46, 56. The sensor connector 66 may also contains the samenumber of contacts on the top receiving portion and on the bottomreceiving portion to operably receive the same number of contacts on thesensor 30. The top and bottom receiving portion of the sensor connector66 may also have the same type of ground and signal configuration as thecorresponding contacts on sensor 30.

The instrument connector 64 and the sensor connector 66 allow theinterconnector 60 to be removed from the resonance shift detector system10 in order to be replaced without affecting the integrity of theinstrument 20 and/or the sensor 30. Since the sensor 30 is removablefrom the interconnector, and in some embodiments intended for a singleuse and therefore disposable, the interconnector 60 may need to bereplaced as a result of normal use. The repeated insertion of a sensor30 into the interconnector 60 may result in the sensor connector 66wearing out under normal use conditions. Other instances may ariseresulting in the advantage of a modular configuration of the resonanceshift detector system 10, including other issues arising with respectonly to the interconnector 60, the interconnector 60 containing softwareapplications that need to be updated, and the like.

In some embodiments, the interconnector 60 contains a read-only memoryon the printed circuit board 62. The read-only memory may serve to setupthe instrument for specific market applications by including software oridentification information that allows the instrument 20 to understandthe particular use of the resonance shift detector system 10 as itrelates to the sensor 30. For instance, the read-only memory may containinformation or explicit instructions for the interpretive logic of theinstrument that relates to the output signal of the sensor 30, which mayserve to limit the resonance shift detector system 10 to specificapplications, such as limited only to use in veterinary applications, asan example. Besides being limited to specific market applications, theinformation on the read-only memory may also serve to limit theresonance shift detector system 10 to specific sub-market applicationsor range of sub-market applications. For instance, within the medicalmarket, certain individuals may not be licensed or qualified to conducta wide range of diagnostic testing; but instead, be limited to certaindiagnostic testing. As a result, the market segment identificationinformation may limit the use of the resonance shift detector system 10to only those proper diagnostic testing applications.

In some embodiments, the interconnector 60 includes an industry standardmeans for capturing patient identification information, such as a barcode or RFID reader. In clinical and hospital settings, the RFID readermay be used for patient identification, identifying the clinic orhospital, healthcare person, and the like.

In some embodiments, besides the sensing resonator 44 and referenceresonator 54, paddle 40 and paddle 50 may also differ from each other inthe contact sets 46, 56 to provide an “on-off” switch mechanism when thesensor 30 is inserted into interconnector 60. For the “on-off” switchmechanism, contact pairs 46 e and 46 f on paddle 40 are connected toeach other, but paddle 50 does not contain the symmetricallymirror-image opposed contact pairs 56 e and 56 f. Instead, paddle 50would contain contacts 56 a-56 d in the same relative position as shownin FIG. 4B with contacts 56 e and 56 f being absent. When the sensor 30with this contact set configuration is inserted into the interconnector60, each of contacts 46 a-46 d engages a respective contact on thesensor connector 66 and contact pairs 46 e and 46 f engages tworespective contacts on the sensor connector 66. On the opposite side ofthe sensor 30, each of the contacts 56 a-56 d also engages a respectivecontact on the sensor connector 66. The contact pairs 46 e and 46 fengaging two respective contacts on the sensor connector 66 while theopposing contacts in the sensor connector 66 are not engaged acts as an“on-off” switch for the instrument 20. The instrument 20 will turn onwhen the sensor 30 is inserted into the sensor connector 66, and theinstrument 20 may be turned off when the sensor 30 is removed from thesensor connector 66. While the sensor 30 may contain more contacts onone side than the other, the resonance shift detector system 10 may beconfigured such that there is no side specific insertion of the sensor30 into the sensor connector 66. Instead, the “on-off” switch mechanismwill work no matter how the contact set side of the sensor 30 isinserted into the sensor connector 66. This eliminates the need for theuser of the resonance shift detector system 10 to know the properinsertion of the sensor 30 into the interconnector 60 other than the endof the sensor 30 with the contact sets 46, 56 being inserted into thesensor connector 66. In some embodiments, the sensor connector 66 andsensor 30 are configured to have a lock-and-key type configuration, suchthat the user is only able to insert the sensor 30 into sensor connector66 in the correct configuration.

The foregoing contact set configuration can also provide a sensor sideidentification feature, such that the instrument 20 is able to identifythe side of the sensor 30 containing the sensing resonator 44 and theside containing the reference resonator 54. In some embodiments, thesensor side is determined by the relationship of the contact sets 46, 56with the contacts on the sensor connector 66 much the same as the“on-off” switch mechanism. The side of the sensor 30 with the sixcontacts will engage the respective six contacts on that specific sideof the sensor connector 66 receiving the sensor 30 indicating thesensing resonator 44 is located on that side of the sensor 30 and/or theside of the sensor 30 with only four contacts will only engage fourrespective contacts on that specific side of the sensor connector 66receiving the sensor 30 indicating the reference resonator 54 is locatedon that side of the sensor 30.

While both the “on-off” switch mechanism and sensor side identifierfeature have been described with respect to the paddle 40 containingboth a sensing resonator 44 and the six contacts 46 a-46 f, the sensor30 may alternatively be configured such that paddle 50 containing thereference resonator 54 contains six contacts 56 a-56 f to provide the“on-off” switch mechanism and/or sensor identifier feature. Similarly,the contact sets may be configured to provide the “on-off” switchmechanism and/or sensor identifier feature without necessarilycontaining six contacts on one of the paddles 40, 50. Instead, it iscontemplated that the sensor 30 may contain more or less than sixcontacts without departing from the scope and spirit of the presentinvention.

One process for the manufacture of the sensor 30 is illustrated in FIGS.11A-11M. In FIG. 11A, individual resonator assemblies may be picked offof a wafer and placed into a waffle pack as illustrated in FIG. 11B. Insome aspects, the wafer is pre-tested such the functional andnon-functional resonator assemblies are known, and the non-functionalresonator assemblies may be discarded. After the resonator assembliesare packed into the waffle pack, they are then picked, as shown in FIG.11C, and placed onto the respective printed circuit board, as shown inFIGS. 11D, at a position where solder flux is spotted onto the printedcircuit board, which serves to adhere the resonator assembly to theprinted circuit board until the melting and reflow of the solder isconducted within a heated oven. In another protocol, the individualresonator assemblies are picked off of the pre-tested wafer and packedinto a tape-and-reel configuration having a linear strip. This processprovides an alternative to the step of picking each resonator out of thewaffle pack to be placed onto a printed circuit board.

FIG. 11E illustrates that the paddles may be manufactured from a panelof printed circuit boards with the resonator assemblies adhered thereto.In another protocol, instead of a panel of printed circuit boards, thepaddles are manufactured from a continuous tape configuration that wouldallow numerous side-by-side paddle configurations. This continuous tapeconfiguration combined with the tape-and-reel configuration allows forefficient manufacture of numerous paddles.

After a panel of paddles is created, a strip or row of paddles isremoved from the panel with all of the resonator assemblies aligned on asingle edge, as illustrated in FIG. 11F. The edge of the strip or row ofpaddles containing the resonator assemblies may then be immersed into anarrow trough, set of test tubes, or other container configurationcontaining one or more desired reagents for preparing the resonatorassembly surface, as illustrated in FIG. 11G. The resonator assembliescantilevered over the edge of the printed circuit board facilitates thisstep. In one aspect, the preparing reagent may be a self-assemblingmonolayer that provides a reactive group on the surface of the resonatorassembly to which a wide range of desired materials may be adhered. Insome aspects, the desired materials may be proteins, DNA, aptamers,lipopolysacharides, biologically active molecules, or other captureligands, depending upon the material to be detected. While theindividual materials or ligands assembled on the surface of theresonator assembly may be on the nano-level scale, the diagnostictesting operates on an aggregate scale on the micro-level by virtue of amicron-sized resonator as the base substrate for the adhered materials.As illustrated in FIGS. 11H-11I, the desired material may be placed ontothe reactive surface of the resonator assembly and bonded with thereactive monolayer to create the desired coating on the respectivesensing or reference resonator. Any excessive amounts of the desiredmaterial not bound to the reactive monolayer may be washed away. Afterthe resonator assemblies are coated with the desired material, theindividual paddles are separated from the strip or row of paddles, asshown in FIG. 11J.

Once the individual paddles are created, a desired sensing paddle 40 anda desired reference paddle 50 is provided and then placed into a sensorhousing assembly 32 in a back-to-back paddle configuration asillustrated in FIGS. 11 k-11L with an intermediate bonding agent asdiscussed above. The resultant sensor 30 within a sensor housingassembly 32 is illustrated in FIG. 11M.

As illustrated in the foregoing disclosure, the back-to-back paddleconfiguration provides a platform to provide numerous different types ofdiagnostic testing depending upon the sensing paddle and referencepaddle. Since there may be numerous sensing paddles and referencepaddles with different coatings on the resonator assemblies, a sensormay be provided for a specific diagnostic test merely by providing theappropriate sensing paddle and reference paddle from inventory. In someaspects, the reference paddle may be matched with numerous differenttypes of sensing paddles depending upon the diagnostic test to beperformed by the resultant sensor. Accordingly, the back-to-back paddleconfiguration provides a universal diagnostic testing platform.

Referring now to FIGS. 12A-12B, in some embodiments, the sensor 30configuration may be an adjacent or side-by-side paddle configurationwith a first paddle 140 mounted adjacent to a second paddle 150. WhileFIGS. 12A-12B illustrate mirror imaged paddles, the first paddle 140 andsecond paddle 150 may have the same relative configuration. In someembodiments, the sensor 30 may contain a sensor housing assembly 132 asillustrated in FIG. 12B. In some embodiments, the sensor 30 may comprisetwo or more back-to-back paddle configurations in a side-by-sideconfiguration.

While the foregoing disclosure has referred to the sensor having atleast one sensing resonator and at least one reference resonatordisposed on a printed circuit board substrate, other substrates arecontemplated by various embodiments of the present invention, including,for example multichip modules, the silicon wafer of the resonatorassembly, or the like. The respective substrate would connect therespective resonator to the instrument through an impedance matchconductor.

During the use of the resonance shift detector system 10, including theportable field-detection embodiments, the insertion of the sensor 30into the sensor connector 66 may turn on the instrument 20 and theinterface screen on the instrument 20 will indicate to the user that theresonance shift detector system 10 is ready to obtain a sample.

During the sampling process, the sensor 30 may be introduced into aliquid or gaseous sample, or the sample aliquot may be introduced to thesensing and reference resonators 44, 54 by way of a sensor housingassembly. The liquid sample for the diagnostic test may include blood,urine, serum, saliva, water, or any other liquid sample that may be ofinterest. As soon as the sample contacts the sensing and referenceresonators 44, 54, there is a change in signal from the resonators 44,54. The instrument 20 is waiting to receive the change in signal, andonce the change in signal is detected, the instrument 20 begins theinterpretative sequence of collecting data. The instrument 20 continuesto collect data until either (i) the instrument 20 times out because thesignal has not changed, or (ii) depending upon the speed with which thesignal changes, the instrument 20 will stop collecting data once enoughdata is received to give an interpretation of the diagnostic test. Aninterpretation of the diagnostic test may include an indication that thetarget material has been bound or captured onto the sensing resonatorand a quantification of the target material.

The embodiments above are intended to be illustrative and not limiting.Additional embodiments are within the claims. In addition, althoughaspects of the present invention have been described with reference toparticular embodiments, those skilled in the art will recognize thatchanges can be made in form and detail without departing from the scopeof the invention, as defined by the claims.

Persons of ordinary skill in the relevant arts will recognize that theinvention may comprise fewer features than illustrated in any individualembodiment described above. The embodiments described herein are notmeant to be an exhaustive presentation of the ways in which the variousfeatures of the invention may be combined. Accordingly, the embodimentsare not mutually exclusive combinations of features; rather, theinvention may comprise a combination of different individual featuresselected from different individual embodiments, as will be understood bypersons of ordinary skill in the art.

Any incorporation by reference of documents above is limited such thatno subject matter is incorporated that is contrary to the explicitdisclosure herein. Any incorporation by reference of documents above isfurther limited such that no claims that are included in the documentsare incorporated by reference into the claims of the presentApplication. The claims of any of the documents are, however,incorporated as part of the disclosure herein, unless specificallyexcluded. Any incorporation by reference of documents above is yetfurther limited such that any definitions provided in the documents arenot incorporated by reference herein unless expressly included herein.

For purposes of interpreting the claims for the present invention, it isexpressly intended that the provisions of Section 112, sixth paragraphof 35 U.S.C. are not to be invoked unless the specific terms “means for”or “step for” are recited in a claim.

What is claimed is:
 1. A sensor for a biosensor instrument, the sensorcomprising: a first paddle assembly comprising a first substrate havinga proximal end, a distal end, a front surface and a back surface, amicrobalance sensing resonator assembly attached to the front surface ofthe first substrate proximate the proximal end, and at least one sensingelectrical contact proximate the distal end in electrical communicationwith the sensing resonator assembly; and a second paddle assemblyconnected to the first paddle assembly, the second paddle assemblycomprising a second substrate having a proximal end, a distal end, afront surface and a back surface, a microbalance reference resonatorassembly attached to the front surface of the second substrate proximatethe proximal end, and at least one reference electrical contactproximate the distal end in electrical communication with the referenceresonator assembly; wherein the first and second paddle assemblies aremechanically arranged relative to one another such that the sensing andreference resonator assemblies are on a proximal end of the sensor; andwherein the sensing resonator assembly comprises at least one sensingresonator coated with a testing material that operably interacts with atarget material, wherein the sensing resonator is constructed such thatit has a resonant frequency in the range of about 0.5-10 GHz.
 2. Thesensor of claim 1, wherein the reference resonator assembly comprises atleast one reference resonator that does not operably interact with thetarget material.
 3. The sensor of claim 1, wherein the first substrateincludes a first printed circuit board.
 4. The sensor of claim 3,wherein the second substrate includes a second printed circuit board. 5.The sensor of claim 4, wherein the first and second printed circuitboards have essentially the same configuration.
 6. The sensor of claim1, wherein the sensing resonator assembly is cantilevered over theproximal end of the first substrate.
 7. The sensor of claim 6, whereinthe reference resonator assembly is cantilevered over the proximal endof the second substrate.
 8. The sensor of claim 1, wherein the sensingresonator assembly is attached in an off centered configuration relativeto a centerline defined along a longitudinal axis of the secondsubstrate.
 9. The sensor of claim 1, wherein the reference resonatorassembly is attached in an off-centered configuration relative to acenterline defined along a longitudinal axis of the second substrate.10. The sensor of claim 1, wherein the microbalance reference resonatorassembly comprises a resonator coated with a reference material.
 11. Thesensor of claim 1, further wherein the proximal end of the firstsubstrate has a first width and the distal end of the first substratehas a second width that is greater than the first width.
 12. The sensorof claim 11, wherein the proximal end of the second substrate has athird width and the distal end of the second substrate has a fourthwidth that is greater than the third width.
 13. The sensor of claim 12,wherein the first and third width are approximately the same.
 14. Thesensor of claim 1, the first paddle assembly having two or more sensingresonator assemblies and two or more sensing electrical contacts inelectrical communication with the two or more sensing resonatorassemblies.
 15. The sensor of claim 14, the second paddle assemblyhaving two or more reference resonator assemblies and two or morereference electrical contacts in electrical communication with the twoor more reference resonator assemblies.
 16. The sensor of claim 1,wherein the proximal end of the sensor is sized to be inserted into awell of a standard 96 well plate.
 17. The sensor of claim 1, wherein theback surface of the first substrate is connected to the back surface ofthe second substrate.
 18. The sensor of claim 17, further comprising abonding agent between the first and second substrates.
 19. The sensor ofclaim 1, further comprising a housing assembly surrounding a portion ofthe sensor, and wherein the at least one sensing electrical contact andthe at least one reference electrical contact at least partially extendsfrom the housing assembly.
 20. A sensor for a biosensor instrument, thesensor comprising: a first paddle assembly comprising a first substratehaving a proximal end, a distal end, a front surface and a back surface,a microbalance sensing resonator assembly attached to the front surfaceof the first substrate proximate the proximal end, and at least onesensing electrical contact proximate the distal end in electricalcommunication with the sensing resonator assembly; and a second paddleassembly connected to the first paddle assembly, the second paddleassembly comprising a second substrate having a proximal end, a distalend, a front surface and a back surface, a microbalance referenceresonator assembly attached to the front surface of the second substrateproximate the proximal end, and at least one reference electricalcontact proximate the distal end in electrical communication with thereference resonator assembly; wherein the first and second paddleassemblies are mechanically arranged relative to one another such thatthe sensing and reference resonator assemblies are on a proximal end ofthe sensor; wherein the sensing resonator assembly comprises at leastone sensing resonator coated with a testing material that operablyinteracts with a target material, and wherein the sensing resonatorassembly is cantilevered over the proximal end of the first substrate.21. The sensor of claim 20, wherein the reference resonator assembly iscantilevered over the proximal end of the second substrate.
 22. A sensorfor a biosensor instrument, the sensor comprising: a first paddleassembly comprising a first substrate having a proximal end, a distalend, a front surface and a back surface, a microbalance sensingresonator assembly attached to the front surface of the first substrateproximate the proximal end, and at least one sensing electrical contactproximate the distal end in electrical communication with the sensingresonator assembly; and a second paddle assembly connected to the firstpaddle assembly, the second paddle assembly comprising a secondsubstrate having a proximal end, a distal end, a front surface and aback surface, a microbalance reference resonator assembly attached tothe front surface of the second substrate proximate the proximal end,and at least one reference electrical contact proximate the distal endin electrical communication with the reference resonator assembly;wherein the first and second paddle assemblies are mechanically arrangedrelative to one another such that the sensing and reference resonatorassemblies are on a proximal end of the sensor; wherein the sensingresonator assembly comprises at least one sensing resonator coated witha testing material that operably interacts with a target material, andwherein the sensing resonator assembly is attached in an off-centeredconfiguration relative to a centerline defined along a longitudinal axisof the second substrate.
 23. A sensor for a biosensor instrument, thesensor comprising: a first paddle assembly comprising a first substratehaving a proximal end, a distal end, a front surface and a back surface,a microbalance sensing resonator assembly attached to the front surfaceof the first substrate proximate the proximal end, and at least onesensing electrical contact proximate the distal end in electricalcommunication with the sensing resonator assembly; and a second paddleassembly connected to the first paddle assembly, the second paddleassembly comprising a second substrate having a proximal end, a distalend, a front surface and a back surface, a microbalance referenceresonator assembly attached to the front surface of the second substrateproximate the proximal end, and at least one reference electricalcontact proximate the distal end in electrical communication with thereference resonator assembly; wherein the first and second paddleassemblies are mechanically arranged relative to one another such thatthe sensing and reference resonator assemblies are on a proximal end ofthe sensor; wherein the sensing resonator assembly comprises at leastone sensing resonator coated with a testing material that operablyinteracts with a target material, and wherein the reference resonatorassembly is attached in an off-centered configuration relative to acenterline defined along a longitudinal axis of the second substrate.24. A sensor for a biosensor instrument, the sensor comprising: a firstpaddle assembly comprising a first substrate having a proximal end, adistal end, a front surface and a back surface, a microbalance sensingresonator assembly attached to the front surface of the first substrateproximate the proximal end, and at least one sensing electrical contactproximate the distal end in electrical communication with the sensingresonator assembly; and a second paddle assembly connected to the firstpaddle assembly, the second paddle assembly comprising a secondsubstrate having a proximal end, a distal end, a front surface and aback surface, a microbalance reference resonator assembly attached tothe front surface of the second substrate proximate the proximal end,and at least one reference electrical contact proximate the distal endin electrical communication with the reference resonator assembly;wherein the first and second paddle assemblies are mechanically arrangedrelative to one another such that the sensing and reference resonatorassemblies are on a proximal end of the sensor; wherein the sensingresonator assembly comprises at least one sensing resonator coated witha testing material that operably interacts with a target material, andwherein the proximal end of the first substrate has a first width andthe distal end of the first substrate has a second width that is greaterthan the first width.
 25. The sensor of claim 24, wherein the proximalend of the second substrate has a third width and the distal end of thesecond substrate has a fourth width that is greater than the thirdwidth.
 26. The sensor of claim 25, wherein the first and third width areapproximately the same.
 27. A sensor for a biosensor instrument, thesensor comprising: a first paddle assembly comprising a first substratehaving a proximal end, a distal end, a front surface and a back surface,a microbalance sensing resonator assembly attached to the front surfaceof the first substrate proximate the proximal end, and at least onesensing electrical contact proximate the distal end in electricalcommunication with the sensing resonator assembly; a second paddleassembly connected to the first paddle assembly, the second paddleassembly comprising a second substrate having a proximal end, a distalend, a front surface and a back surface, a microbalance referenceresonator assembly attached to the front surface of the second substrateproximate the proximal end, and at least one reference electricalcontact proximate the distal end in electrical communication with thereference resonator assembly; and a housing assembly surrounding aportion of the sensor, and wherein the at least one sensing electricalcontact and the at least one reference electrical contact at leastpartially extends from the housing assembly, wherein the first andsecond paddle assemblies are mechanically arranged relative to oneanother such that the sensing and reference resonator assemblies are ona proximal end of the sensor; and wherein the sensing resonator assemblycomprises at least one sensing resonator coated with a testing materialthat operably interacts with a target material.